The question belongs to Electrical Engineering (Linear System).
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Answer:
You need a 120V to 24V commercial transformer (transformer 1:5), a 100 ohms resistance, a 1.5 K ohms resistance and a diode with a minimum forward current of 20 mA (could be 1N4148)
Step by step design:
- Because you have a 120V AC voltage supply you need an efficient way to reduce that voltage as much as possible before passing to the rectifier, for that I recommend a standard 120V to 24V transformer. 120 Vrms = 85 V and 24 Vrms = 17V = Vin
- Because 17V is not 15V you still need a voltage divider to step down that voltage, for that we use R1 = 100Ω and R2 = 1.3KΩ. You need to remember that more than 1 V is going to be in the diode, so for our calculation we need to consider it. Vf = (V*R2)/(R1+R2), V = Vin - 1 = 17-1 = 16V and Vf = 15, Choosing a fix resistance R1 = 100Ω and solving the equation we find R2 = 1.5KΩ
- Finally to select the diode you need to calculate two times the maximum current and that would be the forward current (If) of your diode. Imax = Vf/R2 = 10mA and If = 2*Imax = 20mA
Our circuit meet the average voltage (Va) specification:
Va = (15)/(pi) = 4.77V considering the diode voltage or 3.77V without considering it
<u>Explanation:</u>
5 Horsepower for 30 mins,
(5)(745.7) = 3.7285 KW power delivered
General Efficiency of IC engine = 20%
Power required =
Energy required per week,
=P × Time = 18.64 × 60 × 30 = 33.5565 MJ
Lawn area = (30) (20) = 600
let sunlight hours be 8 hours
Hence, solar power input on lawn,
=5.62×3600 = 20232 kJ//day
energy input in lawn = (600) (20232) (7)
= 84974.4 mJ/week
Chemical efficiency by photosynthesis = 4%
Chemical content in grass = (84974.4) (0.04)
= 3398.97 mJ
Mass of the clippers
pounds
Removing water content,
dried grass clippings
= 11533.25 gallons
Trash cans repaired
By burning the gas, total energy input = 3398.97 MJ × 0.2
= 679.794 MJ
Efficiency of steeling engine = 20%
Energy output by engine = 679.794 ×0.2
= 135.96 mJ
Energy required by mover = 33.5565 mJ
Hence, Energy (output) ⇒ energy required